This invention relates to nitrogen fertilizer containing as an effective component a water soluble initial condensation product obtained by causing formaldehyde to react with urea and manifesting fungicidal property against Pathogenic fungi.
Such water soluble initial condensation product can be obtained by effecting a reaction between 1 mole of urea and 1-2 moles of formaldehyde in an alkaline or neutral state at normal temperature for 15 minutes to several hours, concentrating an aqueous solution of the reaction product under a reduced pressure and then drying. Among the water soluble initial condensation products are included monomethylolurea, dimethylolurea, 1-methylol-methylene-2 urea, 3-methylol-methylene 2 urea, 1,1'-di-methylol-methylene 2 urea, 1,3'-di-methylolmethylene 2 urea. Pure monomethylolurea and pure dimethylolurea isolated from the initial condensation products or a mixture of monomethylolurea and dimethylolurea have the same fungicidal property as the water soluble initial condensation products.